Fireproof sealing materials for vertical shaft cable trays

Modern fireproof sealing for vertical shaft cable trays combines intumescent materials, modular firestop systems, and precise installation techniques to prevent fire and smoke spread in high-rise buildings.

Key Materials and Systems

Intumescent Caulks and Mastics: Products like IC 15WB Caulk expand under heat to seal gaps around cables and trays, effectively containing fire and smoke at the penetration point. These are suitable for both new construction and retrofits, and can be applied with standard caulking tools for precise sealing (Eaton) . Firestop Packs and Mineral Wool: Fire-resistant mineral wool or firestop packs are used to fill larger gaps in vertical shafts. Packing thickness is typically at least 24 cm, and gaps between packs and cables should not exceed 1 cm² to ensure integrity. Fire-resistant backing plates may be installed for large openings to support the seal (AllPCB) . Modular Sealing Systems: Systems like FIRSTO and NOFIRNO provide modular, pre-engineered solutions for multi-cable and cable tray penetrations. These systems use expanding rubber sleeves combined with fireproof sealants to create a tight, reliable seal that is easy to assemble around existing cable runs. They are designed for vertical shafts and can accommodate multiple cables or pipes through the same penetration (CSD Sealing Systems) . Coatings and Elastomeric Sheets: FISSIC Coating® is a water-based, APEO-free fire retardant coating that protects metal surfaces and cable trays from fire and corrosion. 3M Fire Barrier Moldable Putty+ combines elastomeric sheets with steel mesh and aluminum foil for enhanced fire resistance and ease of installation (Eaton) .

Installation Best Practices

• Sequential Packing: Firestop packs should be installed in an orderly sequence to avoid voids. All gaps inside and around metal trunking must be sealed both internally and externally (AllPCB) .
• Waterstop Integration: At slab penetrations, a waterstop of at least 50 mm is recommended to prevent water ingress, with 20–30 mm of firestopping above the tray (AllPCB) .
• Cover Plates: Use square, evenly painted cover plates to close openings, ensuring a uniform and reliable seal (AllPCB) .
• Performance Testing: Fireproof sealing systems should be evaluated for thermal insulation, smoke sealing, and overall integrity. Simulations and entity test platforms can help predict performance under fire conditions, including the effects of gap size on smoke and flame diffusion (MDPI) .

Performance Considerations

The effectiveness of vertical shaft fireproof sealing depends on both material properties and construction quality. Proper installation prevents the chimney effect in cable shafts, which can accelerate fire and smoke spread. Modular systems and intumescent materials provide flexibility for maintenance and retrofitting while maintaining compliance with fire safety standards (MDPI, CSD Sealing Systems) .

Summary

The latest fireproof sealing methods for vertical shaft cable trays integrate intumescent caulks, firestop packs, modular sealing systems, and protective coatings. Key factors include precise gap management, sequential installation, waterstop integration, and performance testing. These approaches ensure fire containment, smoke control, and long-term reliability in high-rise and industrial applications.